Ogre is a giant LTR retrotransposon described in the genome of Pisum sativum (Neumann, Pozarkova and Macas 2003). This element belongs to a lineage of plant LTR retrotransposons (Tat), sibling of other lineage of putative plant endogenous retroviruses (Athila), providing evidence of a shared ancestral lineage originally described as class A by Wright and Voytas (1998). The genomic structure of Ogre is 22.7 Kb in size including LTRs of 5 Kb. The internal region of this element displays a Primer Binding Site (PBS) complementary to a tRNAArg, a Polypurine Tract (PPT) close to the PBS, and three Open Reading Frames for ORF-1, gag/pr and pol (Neumann, Pozarkova and Macas 2003). Ogre also has an Untranslated Region (UTR) of approximately 2.5 Kb between the integrase domain and the 3´LTR.
Figure not to scale. If present, long terminal repeats (LTRs) have been highlighted in blue. Amino acid motifs noted with lines indicate the conserved residues in each protein domain, abbreviations below mean:
|DU or DUT=dUTPase
|TAV or IBMP=transactivator/viroplasmin or inclusion body matrix protein
|PBS=primer binding site
|ATF=aphid transmission factor
|VAP=virion associated protein